Image pickup apparatuses having a so-called Bayer array for obtaining a color image are often used. In an image pickup apparatus of this type, color filters (which may be denoted by CFs) each configured to transmit light of a specific wavelength component, such as light of red, green, or blue color, are arranged on an element surface on a pixel-by-pixel basis. Hereinafter, red, green, and blue colors will be denoted by R, G, and B, respectively. A pixel having a red (R) CF will be referred to as an R pixel, a pixel having a green (G) CF will be referred to as a G pixel, and a pixel having a blue (B) CF will be referred to as a B pixel. The R, G, and B pixels may be collectively referred to as RGB pixels.
Patent Literature 1 describes an image processing apparatus having RGB pixels and pixels with no CFs (hereinafter referred to as white pixels or W pixels). An image pickup apparatus described in Patent Literature 1 performs edge detection and blur correction on signals output by an image pickup element having an RGBW array, so as to perform color correlation re-mosaicing.